Modeling & Testing of the Capsule Parachute Assembly ......PTV Test Sequence 2/22/2013 20 Extraction from C-17 at 25,000 ft with two 28 ft Extraction Parachutes Smart Separation after

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Capsule Parachute Assembly System (CPAS) - ESCG Analysis Team

Modeling & Testing of the Capsule Parachute Assembly System (CPAS)

February 21, 2013

Leah M. Romero – [email protected] – 281-461-5158

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CPAS OVERVIEW

2/22/2013 2

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CPAS Overview Capsule Parachute Assembly System (CPAS) is the

parachute system for the Orion vehicle used during re-entry Similar to Apollo parachute design

Collaboration between NASA JSC, ESCG, and Airborne Systems

2/22/2013 3

A Government Furnished Equipment (GFE) project responsible for: Design Development testing Performance modeling Fabrication Qualification Delivery

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CPAS Concept of Operations

2/22/2013 4

Nominal Mission and High Altitude Abort Deployment Sequence

Low Altitude and Pad Abort Sequence (direct to mains)

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CPAS Analysis Focus Flow from flight performance requirements from the CPAS Project

Technical Requirements Specification (PTRS) Revision Meet during specified failure conditions

Rate of Descent (ROD) Crew and vehicle structure safety

Parachute Loads Drogue and Main single riser loads

Individual parachute failure Drogue and Main cluster loads

Sum of individual riser loads Vehicle structural failure

Rotation Torque Limit Main risers induce rotation Orient vehicle edge into water for landing

2/22/2013 5

Full Open Main

Canopy

Riser

Suspension Lines

Projected Diameter

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Agenda Airdrop Testing

Gen I & II EDU

Parachute Analysis Simulations Preflight Analysis Post-Flight Analysis

Development of a Parachute Model Reconstructions Statistically Derived Parameters

System Verification Future of CPAS

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AIRDROP TESTING

Gen I & IIEDU

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Evolution of Test Vehicles & Techniques

Gen I Objectives1. Characterize single

parachute inflation parameters

2. Demonstrate the system

2/22/2013 8

Gen II Objectives1. Test failure modes2. Investigate potential

design changes

EDU Objectives1. Test representative

parachute systems2. Test failure modes

Smart Separation Objectives1. Test Smart Separation

software and upgraded Avionics suite

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CPAS Parachutes

Extraction Chutes (~28 ft) Pulls the vehicle out of the aircraft. Used for testing only.

Programmer Parachutes Used to create the proper test conditions for the Drogue,

Pilot, or Main chutes. Used for testing only. Can sometimes be an identical chute as the Drogues, but

the use is different. Forward Bay Cover Parachutes (FBCPs) (~7 ft)

Pulls off Forward Bay Cover (FBC) from vehicle Drogue Parachutes (~23 ft)

Stabilizes the vehicle for Main deployment. Pilot Parachutes (~10 ft)

Pulls out the Main chutes. Main Parachutes (~116 ft)

Slow the vehicle to landing

9

Extraction Chute

Programmer Chute

Pilot Chute

Main ChuteNot to Scale

Drogue Chute

FBCP

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AIRDROP TESTING

Gen I & IIEDU

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CPAS Gen 1 and Gen 2 Test ProgressionGen 1 Testing

Gen 2 Testing

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Pilot Chute Tests

Jan – Mar ‘07

Single Main Chute Tests

Aug ‘07 – Jan ‘08

Drogue Chute Tests

Jun – Dec ‘07

Cluster Chute Tests

Oct ‘07 – Jul ’08, May ‘10

4 Tests3 Tests

3 Tests 2 Tests, PA-1, 1 Failed Test

TSE-1 A, B, & C “Smart Separation”

Sept - Dec 20103 Tests

Sept‘ 09 - Mar ‘10

2 Tests, 1 Failed Test

April 2010

2 Tests

July 2010

1 Test

MDT 2-1, 2-2Skipped Stage

CDT 2-1 Main Line Length Ratio

MDT 2-3, CDT 2-2, 2-3 Increased Porosity

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Gen I & II Test Vehicles Each test vehicle was designed to achieve a specific test objective Weight Tub

Test the parachute system with a representative weight Significantly tested and proven operations with a quick turn around

Small or Medium Drop Test Vehicle (SDTV or MDTV) Heritage vehicle from the X-38 program High dynamic pressure

Parachute Test Vehicle (PTV & PTV2) Wake similar to the Orion capsule

2/22/2013 12

Gen II CDT-2-3 Build UpGen II CDT-2-3 CAD

Gen I MDT-3 Build Up

Gen I MDT-3 CAD

Gen I PTV (CDT-2)

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Gen I CPAS PTV Failure (CDT-2) Cause of failure

Inability of programmer to remain inflated due to test vehicle wake Programmer trailing distance was insufficient Stabilization parachutes caused additional, not simulated wake

Contributing factors Late completion of ConOps Small, unproven reefing used on the programmer (20%) Lack of robust extraction and separation simulations

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Boilerplate Failure Recovery Increased knowledge regarding wake effects

Computational fluid dynamics (CFD) anchored to wind tunnel testing

Improved understanding of vehicle separation Smart separation algorithm was created

Validated on 3 Gen II tests – Test Support Equipment (TSE) series Separation simulations

Two-body 6-Degree of Freedom (DOF)Models the separation and close proximity dynamics

Lessons learned from boilerplate failure Smart separation algorithm used to separate the PTV2 from the

CPSS Aerodynamic databases will be based on PTV wind tunnel data Stabilization parachutes will not be used Simulations will account for wake effects All protuberances will be eliminated or rounded

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Gen II Avionics Advancements Data Acquisition System (DAS) - cRIO

Centralized unit for controlling and storing data from multiple instruments Allowed for time-synchronization of data

Larger storage capacity

2/22/2013 15

NovAtel SPAN-SE

Crossbow Nav440

Upgraded Velocity Measurement Instrumentation NovAtel SPAN-SE

Accurate measurement assists in ROD Crossbow Nav440

Higher velocity uncertainties than NovAtel Triggers smart separation

Both are integrated GPS/IMUMitigates drop outs during extraction phase

cRIO

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Gen II Avionics Advancements Upgraded Load Measurements

Gen I used Tension Measuring System (TMS) units attached to each riser - had high uncertainty

Gen II used 30,000 lbf strain links attached between the riser and confluence fitting Provide adequate data for the Main parachutes Provided noisy data on the Drogue parachutes due to the turbulent wake

environment

Increased Fidelity in Atmospheric Data Windpack and balloon released to travel through similar air column

as test Ground weather stations on the drop zone

Anchors windpack and balloons with ground surface winds

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AIRDROP TESTING

Gen I & IIEDU

2/22/2013 17

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EDU Test Vehicles Mid-Air Delivery System (MDS) & Cradle and Platform Separation System

(CPSS) Allows the PCDTV and PTV to be deployed from an aircraft cargo bay

Parachute Compartment Drop Test Vehicle (PCDTV) Tests the full CPAS system utilizing a stable vehicle Dart shape based on the Solid Rocket Booster and Ares booster parachute test

program Allows for achievement of high dynamic pressure

PTV/CPSS Tests the full CPAS system with representative vehicle aerodynamics Unable to achieve high dynamic pressure with current test techniques

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PCDTV Test Sequence

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Extraction

Separation

Programmer Deploy

Drogue Deploy

Pilot Deploy

Main 1st StageMains 2nd StageMains

Full Open

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PTV Test Sequence

2/22/2013 20

Extraction from C-17 at 25,000 ft with two 28 ft Extraction Parachutes

Smart Separation after Ramp Clear

Two Full-Open Gen II Drogues as Programmers deployed

Programmer cut

One Drogue deployed

Smart Drogue Release using SDR

3 Pilots lift 3 Mains with

nominal reefing

PTV Touchdown

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PARACHUTE ANALYSIS

SimulationsPreflight AnalysisPost-Flight Analysis

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Simulation Tools CPAS uses numerous simulation tools for preflight predictions,

mission support, and post-flight data analysis and reconstructions Determine configuration design Ensure safety of test and personnel Assess test objectives and solve unexpected test results Parachute model development

Tools have evolved from low fidelity spread sheets to high fidelity independent parachute simulations

End-to-end trajectories currently require use of multiple simulations Desired to consolidate number of simulations

Many of the simulations are developed and maintained by NASA JSC EG

Support and processing tools developed and maintained by ESCG

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Evolution of Simulation & Analysis Tools

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Gen I

Time 2006 2007 2008 2009 2010 2011 2012 2013Preflight Predictions DSSA v.Beta_5a,

v.Beta_5b4, v.Beta_5b5

v.Beta_8e v.Beta_8f1 v.Beta_8f3, v.Beta_8f5

v.Beta_8g, v.Beta_8g1Monte Carlo capability

v.Beta_8g2 through v.Beta_8g5a

v.Beta_8g6 through v.Beta_8h1 v.Beta_8h1

DTV‐Sim v.14 v.15 v.16 v.17 Monte Carlo capability

Pallet Sim

CAP Sim Separation Simulation

DSS Monte Carlo capability

ADAMSFAST

Mission

Supp

ort X‐38 Legacy

Footprint Tool(Primary) (Primary) (Primary)

Sasquatch(Secondary)

(Primary) Polygons

Pressure Altitude Calculation

Post Flight

Reconstructio

n

Spreadsheets

DSSA v.Beta_8e v.Beta_8f1 v.Beta_8f3, v.Beta_8f5

v.Beta_8g, v.Beta_8g1Monte Carlo capability

v.Beta_8g2 through v.Beta_8g5a

v.Beta_8g6 through v.Beta_8h1 v.Beta_8h1

DTV‐Sim v.14 v.15

DSSFDP v.1.07 v.1.09, v.1.10

BET/BEA/BEW Scripts

ADAMSFAST

Gen II EDU

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PARACHUTE ANALYSIS


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EDU-A-CDT-3-7 Test and Simulation Architecture

2/22/2013 25

PTV/CPSS separation

C-17 with a single 15 ft GFE Drogue parachute

prior to extraction

DSSA/ADAMS ADAMS

Not to Scale

Static-line deploy Two Full Open Programmers

Mortar deploy three CPAS Pilot parachutes

DSS/FAST

Three Pilots deploy Three CPAS Main

parachutesMain Reefing:

.035/.11/1Cutters: 8s/16 s

Mortar deploy CPAS Drogue parachute

Drogue Reefing:.70/1 Cutters: 14s

Extraction parachute cuts away to deploy recovery

parachute

DTV-Sim

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Preflight Predictions: Dynamic Pressure & Altitude

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All cases reach Main steady state above altitude

limit

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Preflight Predictions: Monte Carlo – Loads

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0 valid cases exceed Drogue DLL

0 valid cases exceed Main cluster limit (based on 50/25/25% load share)

High rate case

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Preflight Predictions: Footprint Analysis

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PARACHUTE ANALYSIS


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Post-Flight Data Analysis Windpack and balloon data

BEA: Best Estimate Atmosphere BEW: Best Estimate Winds

Vehicle Data used to create Best Estimate Trajectory (BET) Dynamic Pressure Loads* Drag Area (CDS)*

Photogrammetry Fly-out angles during steady state

*completed for each phase of each parachute2/22/2013 30

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Wind Components Profile (CDT-3-5)

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0 20 40 60 80 1000

5000

10000

15000

20000

25000 Ramp Clear

Main steady-state start

Touchdown

Wind Magnitude (fps)

Alti

tude

(ft -

MSL

)

3AM Balloon, 10:29 UTC4AM Balloon, 11:21 UTC6AM Balloon, 12:42 UTC9AM Balloon, 16:00 UTCWindpack DGPS 139Windpack DGPS 145YPG July Atmosphere +/-3 sigmaBest Estimate Winds

Winds < 30 ft/s mostly out of SW

0 50 100 150 200 250 300 3500

5000

10000

15000

20000

25000 Ramp Clear

Main steady-state start

Touchdown

Wind Direction (deg. true)

Alti

tude

(ft -

MSL

)

N NE E SE S SW W NW

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0 50 100 1500

10

20

30

40

50

60

70

80

90

Sep

arat

ion

Pro

gram

mer

s R

elea

se

Dro

gue

S/N

6 D

isre

ef to

Ful

l

Dro

gue

Rel

ease

Mai

n st

eady

-sta

te

Time (s - RC)

Qba

r (ps

f)

Aircraft Tray SPAN-SESPAN-SE Raw IMUBest Estimate Trajectory (GPS/IMU)DSS Preflight (12/11/2012)

Dynamic Pressure ~11 psf lower than nominal prediction at Main deployment

2/22/2013 32

62 64 66 68 7055

60

65

70

75

80

85

90

Dro

gue

Rel

ease

Time (s - RC)

Qba

r (ps

f)

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Load Scaling

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35 40 45 50 55 60 650

0.5

1

1.5

2

2.5

3x 10

4 D

rogu

e S

/N 6

Dis

reef

to F

ull

Dro

gue

Rel

ease

Time (s - RC)

Chu

te L

oad

(lb)

DSS Preflight (12/11/2012)SPAN-SE Raw IMUDrogue S/N 3 (Bay A) Load CellDrogue S/N 6 (Bay F) Load Cell

35 40 45 50 55 60 650

0.5

1

1.5

2

2.5

3x 10

4

Dro

gue

S/N

6 D

isre

ef to

Ful

l

Dro

gue

Rel

ease

Time (s - RC)

Chu

te L

oad

(lb)

DSS Preflight (12/11/2012)SPAN-SE Raw IMUDrogue S/N 3 (Bay A) Load CellDrogue S/N 6 (Bay F) Load Cell

Before Scaling After Scaling

Scaling due to load cells being below fairlead Energy lost due to friction

Scale loads to match IMU data

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Photogrammetrics Used to characterize Main parachute behavior in a cluster

Quantify fly-out angles, geometric inlet area, and twist angles Understand collisions and other parachute dynamics Rate of Descent (ROD) Reefing line tension

Provides insight into dynamics which is related to data gathered

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Fly-Out Angles During Steady State

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80 100 120 140 160 180 200 220 240 2600

5

10

15

20

25

Mai

n st

eady

-sta

te

PTV

Tou

chdo

wn

Time (s - RC)

Fly-

Out

Ang

le (d

eg)

Main S/N 4 (candystriped)Main S/N 6 (double clocked)Main S/N 9 (double clocked)Main Cluster (avg,spline)Time Average: 16.57 deg

Mains inflating

Collisions

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DEVELOPMENT OF A PARACHUTE MODEL

ReconstructionsStatistically Derived Parameters

2/22/2013 36

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Test Reconstruction Use BEA/BEW/BET

Iterate parachute parameters Automated process Start with latest Model Memo values

Output parachute parameters that cause simulation to match the BET

Parameters are published in semiannual Model Memo Assess parameters through benchmarks

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Finite Mass Inflation Curve Fit1. Determine Parachute Parameters:

Start time, ti

Initial Airspeed, Vi

Drag coefficient from equilibrium velocity, CDo

Time average drag areas Start Drag Area, (CDS)a End Drag Area, (CDS)b Full open drag area, (CDS)o

Or describe area reefing ratios, i, i+1

2. Generate inflation curve with guessed parameters: Fill constant, n Profile shape, expopen, Optional: guess i+1

3. Compute difference between inflation curve and test data

4. Sum the difference to compute area between curves (error)

5. Iterate n and expopen to minimize the error area Optional: optimize i+1

2/22/2013 38

55 56 57 58 59 60 61 62 630

50

100

150

200

250

300

350

400

450

Time (s - RC)

CDS

(ft2 )

Main S/N 6 (Bay E) Load CellMain S/N 6 fit

55 56 57 58 59 60 61 62 630

50

100

150

200

250

300

350

400

450

Time (s - RC)

CDS

(ft2 )

Main S/N 6 (Bay E) Load CellMain S/N 6 fit

(CDS)a

(CDS)b

ti

i

i1iof V

Dnt

expopen

f

iaDbDaDD t

ttSCSCSCtSC

Minimize total area

Initial guess

Optimized

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Main Best Fit Inflation parameters

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78 80 82 84 86 88 90 920

500

1000

1500

2000 M

ain

S/N

3 B

ag S

trip

(vid

) M

ain

S/N

2 B

ag S

trip

(vid

) M

ain

S/N

1 B

ag S

trip

(vid

)

Mai

n S

/N 1

1st

Dis

reef

(vid

) M

ain

S/N

3 1

st D

isre

ef (v

id)

Mai

n S

/N 2

1st

Dis

reef

(vid

)

Time (s - RC)

CDS

(ft2 )

Main S/N 1 (Bay B) Load CellMain S/N 2 (Bay C) Load CellMain S/N 3 (Bay E) Load CellSum of Load CellsDSS Postflight (Mains)Main S/N 1 fitMain S/N 2 fitMain S/N 3 fitDSS CDS exact

89 90 91 92 93 94 95 96 970

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Mai

n S

/N 1

1st

Dis

reef

(vid

) M

ain

S/N

3 1

st D

isre

ef (v

id)

Mai

n S

/N 2

1st

Dis

reef

(vid

)

Mai

n S

/N 2

Dis

reef

to F

ull O

pen

(vid

)

Mai

n S

/N 1

Dis

reef

to F

ull O

pen

(vid

) M

ain

S/N

3 D

isre

ef to

Ful

l Ope

n (v

id)

Time (s - RC)

CDS

(ft2 )


95 100 105 1100

0.5

1

1.5

2

2.5

3

3.5

4

4.5x 10

4

Mai

n S

/N 2

Dis

reef

to F

ull O

pen

(vid

) M

ain

S/N

1 D

isre

ef to

Ful

l Ope

n (v

id)

Mai

n S

/N 3

Dis

reef

to F

ull O

pen

(vid

)

Time (s - RC)

CDS

(ft2 )


Inflation parameters from individual parachute

reconstructions for each stage are recorded in a spreadsheet

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DEVELOPMENT OF A PARACHUTE MODEL

ReconstructionsStatistically Derived Parameters

2/22/2013 40

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Transition from Uniform to Statistical Distributions

2/22/2013 41

0 1 2 3 4 5 6 7 8 9 100

0.5

1

1.5

2

2.5

3

3.5

4

-1

+1

-2

+2-3+3

Canopy Fill Constant, n

Freq

uenc

y

Test DataBest Fit of Test DataMedian: 2.35Mean: 2.79Bounds: 0.90063 6.7474

Bounds(formerly Flight Test Dispersions)

TMIN(1-EF) TMAX(1+EF)

Distribution bounds usually fall between 2 and

3 (equivalent) standard deviations from mean

Left Tail Right Tail

Z % Outside CI Z % Inside CI

-1 31.73% +1 68.27%

-2 4.550% +2 95.45%

-3 0.2700% +3 99.73%

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SYSTEM VERIFICATION

2/22/2013 42

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CPAS Verification & Validation Cycle

2/22/2013 43

1) Design the parachute subsystem2) Test the design thought flight and ground tests3) Development and Qualification test data is gathered4) Document the test data and advancements in parachute physics knowledge5) Verify the parachute subsystem meets flight performance requirements

a) If No, update the document for requirement clarificationb) If No, update the design so that it can meet the requirement

6) Validate flight performance requirements at the integrated Crew Module level7) Conduct integrated flight tests8) Run-for-the-record simulations

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2/22/2013 44

Level Verification ValidationInput

PedigreeResults

UncertaintyResults

Robustness Use HistoryM&S

ManagementPeople

Qualifications

4Numerical error small for all important features.

Results agree with real‐world data.

Input data agree with real‐world data.

Non‐deterministic & numerical analysis.

Sensitivity known for most parameters; key sensitivities identified.

De facto standard.

Continual process improvement.

Extensive experience in and use of recommended practices for this particular M&S.

3 Formal numerical error estimation.

Results agree with experiemental data for problems of interest.

Input data agree with experiemental data for problems of interest.

Non‐Deterministic analysis.

Sensitivity known for many parameters.

Previous predictions were later validated by mission data.

Predictable process.

Advanced degree or extensive M&S experience, and recommended practice knowledge.

2Unit and regression testing of key features.

Results agree with experiemental data or other M&S on unit problems.

Input data traceable to formal documenation.

Deterministic analysis or expert opinion.

Sensitivity known for a few parameters.

Used before for critical decisions.

Estabil ished process.

Formal M&S training and experience, and recommended practice training.

1Conceptual and mathematical models verified.

Conceptual and mathematical models agree with simple referents.

Input data traceable to informal documenation.

Qualitative estimaes.

Qualitative estimates.

Passes simple tests.

Managed process.

Engineering or science degree.

0 Insufficient evidence.

Insufficient evidence.







Supporting EvidenceM&S OperationsM&D Development

DSS Credibility Assessment Score (CAS)

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FUTURE OF CPAS

2/22/2013 45

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Future of CPAS

Simulation & Model development Transition to end-to-end simulation in an independent parachute

model Time varying ROD model using fly-out angles Refinement of statistically derived dispersions

2/22/2013 46

Testing EDU (plan as of Feb 6, 2013)

2013: 3 tests – 2 PTV, 1 PCDTV 2014: 5 tests – 4 PTV, 1 PCDTV

Includes first Forward Bay Cover (FBC) test

2015: 2 tests – 2 PTV EFT-1 in fall 2014

CDR Qualification Tests

Lockheed Martin’s MPCV

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SPECIAL THANKS

CPAS Analysis TeamPat GalvinEric RayKristin BledsoeUsbaldo FraireJoe VarelaJohnny BlaschakFernando Galaviz

Koki MachinMike FrostadEntire CPAS team

2/22/2013 47

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For More Information… 2009 AIAA ADS Conference

Overview of the Crew Exploration Vehicle Parachute Assembly System (CPAS) Generation I Drogue and Pilot Development Test Results, R. Olmstead

Overview of the Crew Exploration Vehicle Parachute Assembly System (CPAS) Generation I Main and Cluster Development Test Results, K. Bledsoe

2011 AIAA ADS Conference Proposed Framework for Determining Added Mass of Orion Drogue Parachutes, U. Fraire Summary of CPAS Gen II Testing Analysis Results, A. Morris Load Asymmetry Observed During Orion Main Parachute Inflation, A. Morris Challenges of CPAS Flight Testing, E. Ray Verification and Validation of Requirements on the CEV Parachute Assembly System Using Design of Experiments, P. Schulte Development of Monte Carlo Capability for Orion Parachute Simulations, J. Moore Photogrammetric Analysis of CPAS Main Parachutes, E. Ray A Hybrid Parachute Simulation Environment for the Orion Parachute Development Project, J. Moore Measurement of CPAS Main Parachute Rate of Descent, E. Ray Development of the Sasquatch Drop Test Footprint Tool, K. Bledsoe Development of a Smart Release Algorithm for Mid-Air Separation of Parachute Test Articles, J. Moore Simulating New Drop Test Vehicles and Test Techniques for the Orion CEV Parachute Assembly System, A. Morris Verification and Validation of Flight Performance Requirements for Human Crewed Spacecraft Parachute Recovery Systems, A. Morris

2013 AIAA ADS Conference Extraction and Separation Modeling of Orion Test Vehicles with ADAMS Simulation, U. Fraire An Airborne Parachute Compartment Test Bed for the Orion Parachute Test Program, J. Moore Application of a Smart Parachute Release Algorithm to the CPAS Test Architecture, K. Bledsoe Application of Statistically Derived CPAS Parachute Parameters, L. Romero A Boilerplate Capsule Test Technique for the Orion Parachute Test Program, J. Moore Testing Small CPAS Parachutes Using HIVAS, E. Ray Improved CPAS Photogrammetric Capabilities for Engineering Development Unit (EDU) Testing, E. Ray Reefing Line Tension in CPAS Main Parachute Clusters, E. Ray Skipped Stage Modeling and Testing of the Capsule Parachute Assembly System, J. Varela Reconstruction of Orion EDU Parachute Inflation Loads, E. Ray

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QUESTIONS?

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BACKUP

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Parachute Deployment Envelope

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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

5000

10000

15000

20000

25000

30000

35000

40000

5 psf

15 ps

f

30 ps

f

70 ps

f

115 p

sf13

0 psf

167 p

sf20

4 psf

300 p

sf

Mach Number (nd)

Alti

tude

(ft -

MSL

)

PCDTV: CDT-3-1 (9/8/2011)PCDTV: CDT-3-2 (12/20/2011)PTV: CDT-3-3 (2/29/2012)PCDTV: CDT-3-4 (4/17/2012)PTV: CDT-3-5 (7/18/2012)PCDTV: CDT-3-6 (8/28/2012)

Drogue contingency deploy envelope

Pilot/Main deploy envelope

Drogue mortar fire

Pilot mortar fire

Main inflation

Nominal Entry Drogue Deploy

PCDTV 35K LVAD

Orion Nominal

Entry

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Gen I Helicopter Tests Helicopter tests were simple to execute and analyze

Test Conducted Pilot Development Tests (PDT)

Vehicle used: SDTV Drogue Development Tests (DDT)

Vehicle Used: MDTV

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Small DTV Suspended Beneath UH-1

Programmer parachute set up the desired dynamic pressure Poor understanding of programmer

drag lead to a failure to achieve the desired test condition

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Gen I LVAD Platform with Weight Tub Low Velocity Aerial Delivery (LVAD)

Certified US Army cargo aircraft extraction method

Uses a Type V platform and standard Army extraction parachute

Short Platforms (12 ft by 9 ft platform) Significant pitch under the programmer by

~180º Pilot or Main parachute slings could have

been severed Near-failure causes

Unstable & not well-characterized aerodynamics

Programmer trailing distance from platform Changed on MDT-2 with no significant

stability increase Programmer size

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MDT-1 During Main Deploy

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Gen I/II Missile Shaped Vehicles Cradle Monorail System (CMS)

Allowed the MDTV to be deployed by a C-130A aircraft Constructed on a 32 ft by 9 ft Type V platform to use the LVAD extraction

technique

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No separation simulation created Used low fidelity analysis

methods and engineering judgment

Separation occurred at the time of lowest dynamic pressure predicted in preflight simulations

Assumed an instantaneous separation

Post-test analysis proved that separation occurs in 1.5 seconds

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Summary of Generation II Tests

Test NameNumber of Parachutes

Vehicle Type Primary Test ObjectiveProgrammer Drogues MainsMDT‐2‐1 1 Drogue 1 1 MDTV/CMS Main skipped 1st reefing stageMDT‐2‐2 1 Drogue 1 1 MDTV/CMS Main skipped 2nd Stage MDT‐2‐3 0 1 1 MDTV/CMS Increased Main PorosityCDT‐2‐1 0 2 2 Weight Tub Main Modified Line Length CDT‐2‐2 0 2 2 Weight Tub Increased Main PorosityCDT‐2‐3 0 2 3 Weight Tub Increased Main Porosity

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MDT – Main Development Test MDTV – Medium Drop Test VehicleCDT – Cluster Development Test CMS – Cradle Monorail System

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MDS (Mid-Air Deployment System) Sequence

MDS under extraction parachutes

(post separation) StabilizationParachutes deployed

Recovery chutes

deployed

Recovery chutes 1st Stage

Recovery chutes 2nd Stage

Recovery chutes disreef to

Full Open

MDS touchdown

Extraction

Separation

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CPSS Test Sequence

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Extraction from C-17 at 25,000 ft with two 28 ft Extraction Parachutes

Smart Separation 2.235 s after Ramp Clear

Reposition to backstop 75.1 s

after Ramp Clear

Extraction chute cutaway, recovery chute deploy 128 s after Ramp Clear

CPSS touchdown 330 s after Ramp

Clear

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Trajectory Simulations CAPSIM & PalletSIM

Used to independently model two-vehicle systems post separation

Not used in EDU test phase

DSS High fidelity 6-DOF trajectory simulation Does not have multi-body capability Uses a composite model approach to simulation

parachute clusters

ADAMS Commercial multi-body simulation Models contact forces between bodies Used for EDU extraction and separation phases

Flight Analysis and Simulation Tool (FAST) 6-DOF multi-body trajectory simulator Utilizes Lockheed Martin developed hi-fi

parachute model Currently being phased in as primary tool for

preflight predictions

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CAPSIM GUI

ADAMS Overlay

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Trajectory Simulations Decelerator Simulation System Application (DSSA)

Provides end-to-end 6-DOF simulations of Type V LVAD tests Includes an aircraft extraction model Uses DSS parachute model

DTV-Sim 2-DOF simulation without an aircraft extraction model Provides a point mass trajectory of any vehicle type Uses DSS parachute model

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DSSA GUIDTV-Sim GUI

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Dra

g A

rea,

CDS

Time, t

expopen = 1expopen < 1expopen > 1

expopen = 0.5

expopen = 1.5

Factor DefinitionCD Drag coefficient (of full open parachute)

n Canopy fill constant

expopen Opening profile shape exponent

Ck Over-inflation factor

tk Time to ramp down after stage over-inflation

Parachute Parameters

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Day of Flight Simulations & Lessons Learned Wind data

Preflight predictions are done concerning wind contingency release altitudes

Wind measurements gathered hourly from RAWIN balloons Balloon data is input into Sasquatch to determine the test article

footprints Ground winds can cause parachute and test vehicle damage

Tests are timed to occur immediately after sunrise when winds are at a minimum

Release altitudes Gen I and II data showed higher than planned release altitudes Changes were made to provide the air crew with an indicated

pressure altitude instead of the previously used geometric altitude Tests have shown that this procedure causes vehicles to be dropped

at the planned altitude

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-114.32 -114.3 -114.28 -114.26 -114.24 -114.22

33.3

33.32

33.34

33.36

33.38

33.4

33.42

33.44

33.46

Longitude (deg)

Latit

ude

(deg

)

Aircraft Tray SPAN-SEC-17 On-board AvionicsBest Estimate Trajectory (GPS/IMU)PTV TouchdownRangeKTMKTM Keep OutClearedBLMRelease point

-114.32 -114.3 -114.28 -114.26 -114.24 -114.22

33.3

33.32

33.34

33.36

33.38

33.4

33.42

33.44

33.46

Longitude (deg)

Latit

ude

(deg

)

4AM Balloon, 10:50:52 UTC5AM Balloon, 11:47:07 UTC6AM Balloon, 12:36:41 UTC7AM Balloon, 13:31:20 UTC9AM Balloon, 16:00:34 UTC11AM Balloon, 17:57:06 UTCWindpack DGPS 111Windpack DGPS 139RangeKTMKTM Keep OutClearedBLM

Map of Soundings and PTV Flight

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Windpacks released

Windpacks touchdown

PTVreleased

Actual PTVtouchdown

RAWIN release point

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Parachute Reconstruction Process

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Parachute Data• Riser and Resultant Loads

Fi• Steady-State Drag Area

Computed Parachute Performance• Steady-State Reefed Drag Area

(CDS)R• Steady-State Full Open Drag Area

(CDS)o• Reefing Ratios

i = (CDS)R / (CDS)o• Over-Inflation Factors (infinite mass only)

Ck = (CDS)peak / (CDS)R

Guess Inflation Parameters(e.g. from Model Memo)

• Canopy Fill Constantn

• Opening Profile Shape Exponentexpopen

• Fall Time (infinite mass only)tk

Output Optimized Constants for Stage j

• Canopy Fill Constantn

• Opening Profile Shape Exponentexpopen

• Fall Time (infinite mass only)tk

• Stage Initial AirspeedVi

DSS Input File

Stage Comparison• Do peak parachute loads match?• Does Altitude match?• Does dynamic pressure match?

DSS 6-DOF Trajectory

Drag Area Optimization Process• ‘fminsearch’ function• Minimize error between computed and test (CDS)(t)

Drag Area Simulations for Stage j in MATLAB• Canopy fill time

• Parachute Drag Area Growth

• Drag Area Ramp Down Curve (infinite mass only)

expopen

f

iaDbDaDD t

ttSCSCSCtSC

kifp ttttkpeakDD CSCtSC

i

i1iof V

Dnt

Reconstruction Complete

YES NO

Initial Conditions from BET• Altitude

H• Velocity & Airspeed

VEast, VNorth, Vz, Vair• Attitudes

, , • Body Rates

P, Q, R

NO

YES

Stages Completed?

Continue to next stage

Modify fill constants using engineering judgment

qGWF

)SC( i,pii,pD

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CPAS Flight Performance Requirements Probability of meeting

requirements Loads

Probability per table with 50% confidence

ROD (planned for Rev C) 99.87% probability of

meeting the requirement with 90% confidence

Torque (planned for Rev C) 99.87% probability of

meeting the requirement with 90% confidence

Necessitates the use of statistical assessments

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Uniform Dispersions Previous Model Memos included uniform dispersions

Design dispersions – maximum and minimum seen in test Flight test dispersions – engineer factor around design dispersions

5% for CDS 10% for other parameters

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Further Updates to Statistical Dispersions

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Test Datalogn: 0.9209 0.44781Bounds: 0.90063 6.7474Median: 2.41

Test Datalogn: 0.14547 0.21556Bounds: 0.76275 1.8689Median: 1.17

0 2 4 6 8 100

0.5

1

1.5

2

2.5

3

EDU Main Stage 3 n

EDU

Mai

n St

age

3 ex

pope

n

Documents

Modeling & Testing of the Capsule Parachute Assembly ......PTV Test Sequence 2/22/2013 20 Extraction from C-17 at 25,000 ft with two 28 ft Extraction Parachutes Smart Separation after